Mozambique

Mozambique hosts the southern extension of the East African Rift System and is one of the most seismically active countries in southern Africa. The rift enters Mozambique through Lake Malawi (Lake Nyasa) in the north and bifurcates southward into several arms that extend toward the Mozambique Channel. The Luangwa Rift in northwestern Mozambique and the Urema Trough — within which the Zambezi River flows and which hosts the Gorongosa National Park — are both active rift structures bounded by normal [[fault]]s capable of generating moderate-to-large earthquakes.

The country's most significant seismic event in the modern era occurred on 22 February 2006, when a magnitude 7.0 earthquake struck the Machaze district of Manica Province in western Mozambique. The earthquake killed at least 4 people and injured approximately 40, a relatively low casualty toll given the magnitude, because the [[epicenter]] was in a sparsely populated rural area. The earthquake was preceded by foreshocks and followed by an extensive [[aftershock]] sequence, including events of magnitude 5.5 and above. Geodetic measurements revealed significant coseismic surface deformation consistent with normal faulting on a north-south-trending fault.

In March 2019, Cyclone Idai struck central Mozambique, devastating the city of Beira and surrounding areas in one of the most destructive tropical cyclones in African history. While this was a meteorological disaster rather than a seismic one, the vulnerability of Mozambican infrastructure to natural hazards was starkly revealed. The coincidence of multiple hazards — seismic, cyclonic, and flood — makes Mozambique one of Africa's most disaster-prone environments.

Historically, the Mozambique channel has experienced several moderate-to-large earthquakes. A magnitude 7.0 event struck near Cabo Delgado in northern Mozambique in January 2019, damaging buildings in Macomia and other coastal towns and triggering concerns about [[tsunami]] generation in the Mozambique Channel. The northern coast of Mozambique, particularly in Cabo Delgado Province, faces both seismic hazard and tsunami exposure because the narrow Mozambique Channel can efficiently channel tsunami waves.

The Urema Rift, which traverses Sofala and Manica provinces, is the most studied active rift segment within Mozambique's borders. The Urema Trough contains the Gorongosa caldera and associated volcanic features, as well as a north-trending system of normal faults with estimated Quaternary slip rates. Earthquake focal mechanisms from the Urema region show predominantly normal faulting consistent with east-west extension.

[[seismic-wave]] propagation in Mozambique is complex because the lithosphere transitions from the thick cratonic roots of the Zimbabwe and Kaapvaal cratons in the south to the younger, thinner rift lithosphere in the north. This change in lithospheric properties affects how seismic energy is transmitted and attenuated across different parts of the country. The coastal zone of Mozambique is underlain by thick Cenozoic and Mesozoic sedimentary sequences deposited along the passive margin, and these soft sediments can amplify shaking from moderate earthquakes.

The tectonic framework of Mozambique involves the slow separation of the Nubian and Somalian plates, with extension occurring primarily along the rift faults in the north and central parts of the country. The southern part of Mozambique approaches the stable interior of the southern African craton and experiences progressively lower seismicity southward. The [[epicenter]]s of instrumentally recorded earthquakes in Mozambique define the rift geometry clearly, with clusters in the Malawi Rift transition zone, the Urema Trough, and scattered events along the Mozambique coastal margin and in the Makonde Plateau region.